Developments in LTE are also going to have a significant impact on the unlicensed spectrum, which is currently used by billions of people through their WiFi modems and WiFi services in cities, cafes, airports and other venues.

Known as LTE Unlicensed (LTE-U) or Licensed-Assisted Access (LAA), this technology can also ride on top of WiFi networks (without utilising the mobile service), providing high-speed broadband access to users. It uses the carrier aggregation (CA) function between the unlicensed and licensed spectrum bands. This could be used in relation to distance (where the mobile signal can't reach), in the case of overcrowded signals (e.g. in sports venues), or within buildings and other hard-to-reach places.

The whole reasoning behind the availability of unlicensed spectrum is that it can be used by anybody, including the carriers. But obviously the WiFi industry is worried that this will impact on their businesses. Some countries do have guidelines regarding the use of unlicensed spectrum, but others — namely the USA — do not.

The LAA technology requires new hardware in both the user device and the operator's access point — meaning that customers would have to buy a new phone, and operators would also have to install a new base station or small cell, before you could enjoy faster downloads. There is not yet a standard for the technology, but several carriers have indicated they would like to start to use the new technology in 2016.

A group of mobile operators from Europe, USA and China are proposing to use LAA as a secondary carrier. As my colleague Fred Goldstein explains:

They're trying to prevent LAA from being standardised on strictly unlicensed spectrum. CA (carrier aggregation) means that there are two different frequencies in use; limiting LAA to CA means that it's only a secondary carrier.

There are two major reasons why this change potentially is a good thing.

One is that LTE simply won't work well on unlicensed spectrum alone. Like other mobile standards, LTE assumes that the carrier controls the spectrum it uses, and doesn't have to contend with others' uncoordinated transmitters. LAA thus maintains the connection on licensed frequencies and only uses unlicensed opportunistically, for additional download capacity. Purely unlicensed would not be reliable enough.

Second is that the unlicensed spectrum is more precious than licensed. In some countries, such as the Netherlands and the USA, the 5 GHz band is already getting badly cluttered by cable WiFI access points. Standalone LTE-U could really hurt it. But LAA with CA views itself as a secondary user, and doesn't transmit over other users. It makes at least some effort to be polite about sharing the band, and can do so easily enough since there is another carrier that it can fall back on. Standalone LTE-U wouldn't be able to do that.

Obviously there is still a lot of anxiety amongst the WiFi players in the market, as the mobile operators certainly don't have a good reputation when it comes to sharing and cooperating with others; nevertheless the currently proposed step is in the right direction.

By Paul Budde, Managing Director of Paul Budde Communication Paul is also a contributor of the Paul Budde Communication blog located here. Visit Page

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